This application is based on and incorporates herein by reference Japanese Patent Application No. 2001-319747 filed on Oct. 17, 2001.
The present invention relates to a transparent molded plastic article that has a surfactant layer on a surface of it in order to eliminate static electricity.
Conventionally, a surfactant is coated as an anti-static agent on the surface of, for example, the glasses used in auto instruments to prevent foreign objects from sticking to the surface. In the latest instruments, plastic is commonly used for components such as a meter dial, a meter display pane, and a meter display-panel cover of an auto instrument because plastic is relatively light and affordable. In addition, plastic components are usually made by printing or painting transparent molded plastic bodies, so the instruments are more harmfully influenced by static electricity. Moreover, the instruments are usually assembled by press-fitting, screwing, and so on, so foreign objects such as a shaved flake and a fragment during the assembly stick to the surfaces of the plastic components due to static electricity. Thus, it is inevitable to coat a surfactant as an anti-static agent on the surfaces of the plastic bodies to eliminate static electricity. However, surfactant layers on the plastic components tend to lose transparency due to the time-dependent deterioration of the surfactant, so the plastic components with a surfactant layer tend to be disfigured as time goes by.
The present invention has been made in view of the above aspect with an object to provide a transparent molded plastic article that includes a surfactant layer and is substantially static-electricity-free and disfigurement-free.
In the present invention, a transparent molded plastic article includes a transparent molded plastic body and a surfactant layer, which is located on a surface of the plastic body. The surfactant layer contains a quaternary ammonium salt having a mean molecular weight of 260 to 385 to eliminate static electricity of the plastic body.